Coffee maker



I. JEPSON COFFEE MAKER Jan. 5, 1954 4 SheetsSheet 1 Filed Dec. 51, 1947 Jan. 5, 1954 l. JEPSON 2,664,811

COFFEE MAKER Filed Dec. 31, 1947 4 Sheets-Sheet 2 jig. 3

in. V ll/III" 4? MAX/MUN 3 WITCH OFF .2

PRESS I B A MAX/HUM Q ll 5*- @S.

I. JEPSON COFFEE MAKER Jan. 5, 1954 4 Sheets-Sheet 3 Filed Dec. 31, 1947 lllll INVENTOR. c7210? By %W Jan. 5, 1954 1. JEPSON 2,664,811

COFFEE MAKER Filed Dec. 31, 1947 4 Sheets-Sheet 4 K J \JOZ INVEN TOR. Mr e/p draw 7 &

Patented Jan. 5, 1954 COFFEE MAKER Ivar Jepson, Oak Park, Ill., assignor to Sunbeam Corporation, Chicago, 111., a corporation of Illinois Application December 31, 1947, Serial No. 7 94,959

13 Claims. 1

The present invention relates to automatic cooking devices and more particularly to beverage brewers and coffee makers of the type in which the heating means is automatically controlled during the coffee-making operation.

The present invention is a continuation in part of an application for Letters Patent of the United States, now abandoned, Serial No. 459,761 filed September 26, 1942, and assigned to the same assignee as the present application.

Beverage brewers and coffee makers of the socalled vacuum type have been extensively used in recent years. In general, this type of coffee maker has comprised a lower heating chamber and an upper coffee infusion chamber. Conventionally, water is placed in the lower heating chamber while the coffee grounds are placed in the upper chamber. As the water is heated in the lower chamber, water vapor pressure is created above the liquid in this chamber which,

when the temperature approaches the boiling point of water, forces the water into the upper chamber to infuse the coffee grounds placed therein. When the heat is removed from the lower chamber it cools so that the water vapor contained therein condenses to create a vacuum, thereby causing the coffee to pass from the upper chamber through a suitable filter into the lower chamber where it may be maintained at a desirable temperature of the order of 180 F.

It will be understood that in automatic coffee makers of the type referred to above, it is essential that the heat supply to the heating chamber be cut off when the water has substantially all been forced into the upper chamber. If this cut-off action occurs too soon, substantially all of the water will not have been forced to the upper chamber and the coffee will be diluted by the water remaining in the lower chamber when the coffee returns to the lower chamber. On the other hand, if the cutoff, action is delayed for any appreciable period of time after all the water is forced out of the lower chamber or vessel, damage or destruction of the coffee maker may result, particularly if the conventional glass vessels are employed. Actually, there are on the market today two types of automatic coffee makers of the general class referred to above. In one type the chambers are made of metal and the heating element is built into the bottom of the lower metal chamber. An example of this type of coffee maker is disclosed and claimed in United States Letter Patent 2,312,555 Jepson assigned to the same assignee as the present application. In this type of coffee maker, it will 2 be understood that when substantially all of the water has been forced from the lower chamber, a very rapid increase in the temperature of the metal base will result and such rapid increase in the temperature of the base is utilized to actuate a thermostatically controlled switch for shutting off the heat at the proper time. Although this type of coffee maker operates very satisfactorily in every respect it does involve relatively expensive construction requiring accurate factory adjustment of the parts. It would be desirable to provide a satisfactory coffee maker of less expensive construction employing vessels of glass, plastic, or non-metallic materials, and

control means which may be adjusted accurately in a simple manner.

The other type of coffee maker of the general class described above comprises vessels or chambers of glass together with an electrical heater which is incorporated in a separate stove-like unit. It is apparent at once that a difiicult problem of control arises in this type of coffee maker because of the remote relationship of the electrical heater with respect to the interior of the lower water heating vessel. Numerous means of control have been employed with this second type of coffee maker where glass vessels are used. One common expedient has been to employ a float in the lower vessel which indicates the level of the water in the lower vessel, together with means to actuate a switch when the float has moved to its lowermost position. Such last mentioned means have been relatively complicated and have often comprised magnetic devices exerting electromagnetic forces through the glass container walls to perform a switch control function. Furthermore, such float control devices complicate the apparatus from the standpoint of washing and cleaning the same.

Other liquid level devices have also been suggested such, for example, as contacts which are normally bridged by the liquid in the lower vessel, and when the liquid falls to the desired low lever, the circuit is interrupted to permit a control operation. Such apparatus provides a positive control but, unfortunately, the conductivity of the water is not sufliciently good in all localities to produce the desired control operation.

Pressure responsive devices have also been suggested whereby when the pressure in the lower vessel has reached a predetermined high value, the heating device is rendered ineffective. Unfortunately, such pressure responsive devices have not been positive in operation heretofore so as to shut off the heating device substantially when all of the water has been removed from the lower vessel. Such pressure responsive devices have been set for a predetermined pressure, such, for example, as a pressure of 2 inches of mercury. When the coffee maker is employed to make a large quantity of coffee, such as eight cups, for example, this pressure might be attained long before all ofthe water has been removed from the'lower vessel. On the other hand, if the coffee maker is employed to make only two cups of coifee, for example, this pressure might never be attained so that the pressure responsive device would never operate to shut oif the heat. In addition-to the'variations in the amount of coffee which is madewith the coffee maker, such pressure responsive devices would also be effected by the voltage regulation of the source of electrical energy employed, whereupon the operating pressure might be reached too soon or never be reached, depending uponlwhetherthere is an-under or .an over-voltage condition.

'It would desirable to provide'an automatic coffee maker which was relatively inexpensive and yet which would include means for automatically controlling theheating device at the desired time under all conditions of operation without employing the complicated float control and. similar devices employed heretofore. It would,'furthermore, :bedesirable to provide an automatic coffee maker. of the glass type which would not require the separate stove-like unit which prior art devices employed.

.:It has been discovered that during a coffeemaking operation .of the coffee maker of the type referred to above, the pressure in the lower vessel rises first slowly :and then more rapidly toamaximum value,.which-maximum value may vary widely .under various conditions. It has furthermore been discoveredthat when the water has substantially all been moved to the upper vessel so as to uncover the tube depending into the .lower vessel, .a fairly rapid drop in pressure results. The present invention is primarily concerned .with .the provision of a positive pressure responsive means for controlling an automatic cofiee. maker in which the pressure responsive means operates. directly-in response to a decrease in pressure in the lower vessel following the attainment of a maximum pressure therein. With the present arrangement, as will become apparent from the following description, it is substantially immaterial as to what the value of the maximum pressure should be in any case since the device is responsive to a decrease in pressure.

Accordingly, it is an object of the present invention to providea new and improved automatic coffee maker.

It isanother object of the presentinvention to provide a coflee makerof-the so-called vacuum type in which the heating device is rendered ineffective when substantially all of the liquid in the lower vessel has been displaced to the upper vessel, which resultis accomplished with simple control means, inexpensive .to make, foolproof in operation, ,and satisfactory in every respect.

Anotherobject of the present invention is to provide an automatic coffee maker in which automatic control means responsive to a decrease in pressure following the attainment-of a maximum pressure in the .water heating chamber is employed to control automatically the heating means.

Still anotherobject of the present invention :is

to provid in a coffee maker a novel unit of as-' sembly connected by a supporting structure adapted to be applied to the lower vessel and equipped with an immersion heater depending into the vessel through the open top thereof, together with improved means for controlling the operation of the immersion heater.

A further object of thepresent invention comprises the provision in an automatic coffee maker of a pair of glass vessels together with a unitary assembly including all of the control and heating vmechanisms as well as the apparatus for relating the two vessels during a coffee-making operation.

ltis another object of the present invention to provide an assembly unit embodying a pressure responsive device, a switch device, and a heater unit for detachable application to the open-top of a glass heating vessel which comprises all of the control mechanism for an automaticv coffee maker.

A;further object ofthe present inventionisto provide an improved inexpensive .coifee making vessel for an automatic coffeemaker.

Further objects-and'advantagesof the present invention will become apparent as the following description proceeds and the features of novelty which characterize the inventiomwill be pointed out with particularity in .the claims ,annexed to and forminga part ofthis specification.

For a better understanding-of the present invention, reference may be had tothe. accompanying drawings in which:

Fig. 1 is a side elevational view partly in section' of a vacuum type automaticcoifeemaker embodying the present invention;

Fig. .2 is a fragmentarvsectional .view..taken on line 22 of Fig. 1;

Fig. 3 .isa view looking downward with refer: ence to the lower vesseland takensubstantially along the.line.33 ofllig. 4.

Big. 4is.,a sectional viewtaken on lineA-A of Fig. 3 and assuming that Fig. 3 shows the complete structure;

Figs.,5 andBarepartial views of Fig.4 showing different -control positions of the control mechanism associated therewith;

Fig. '7 is a schematic diagram of the electric control circuit of the automatic coffee makerof the present invention;

Fig. 8 is a graph vorcurve diagram showingthe internal pressure in the lower vessel with reference to time during a coffee making operation to .aid in understanding the operation of the automatic cofiee maker of the present invention;

Fig. .9 is an elevational view similar to Fig. 1 showing another embodiment of the present invention;

Fig. 10 is a top partial view of thelower vessel ofiFie- 9;

Fig. 11 is a partial sectional view taken on line H.- 'l.l of Fig. 10;

'Fig. ,121is a partial view somewhat similar to Fig. 3 of the coffeemaker of Fig. 9; and

(Fig. 13 is an elevational view partly in section of a modified construction embodying the present invention.

Although the present inventionis illustratediri the drawings specifically as applied to an automatic coffee maker of the vacuum ,type .it should be understood that the invention is applicable 'to other types of coffee makers as well as other cooking-devices wherein a cooking operation may be controlledin the manner contemplated by the present invention.

Referring now to the embodiment :of the present invention illustrated in Figs. 1 to 7 inclusive of the drawings where like parts are designated by the same reference numerals there is illustrated a coffee maker comprising a lower water heating chamber or vessel l l and an upper coffee infusion chamber or vessel 12. Preferably these vessels are made of glass although any other suitable material might be employed. The chamber I2 is provided with the conventional depending tube l3, which is adapted to be inserted into the lower vessel II as illustrated in Fig. l of the drawings to provide communication between the vessels H and [2. This tube l3 may be provided with a suitable opening 13a such as is disclosed in Fig. 1 of Jepson Patent 2,312,555 assigned to the same assignee as the present invention to permit a predetermined heating of the water in the vessel H before the water is forced into the vessel [2. As illustrated the lower vessel l I has an open top 14 defined by an upright flange I5. In accordance with one aspect of the present invention there is provided a unit of assembly generally designated at i6 which unit and the two vessels I l and I2 effectively comprise the entire coffee maker. This unit of assembly [6 includes an upwardly extending annular flange ll which is adapted to receive a resilient sealing ring l8 which fits over the tube l3 adjacent the bottom of the vessel :2 when the vessels are assembled in the manner shown in Fig. l of the drawings. With this arrangement the vessels are related in sealed relationship with a means of communication provided therebetween. Preferably the annular flange ll which provides a seat for the resilient sealing ring 18 includes a deformed portion 2l which defines a suitable pouring spout for the lower vessel.

As illustrated the upper vessel [2 is provided with a suitable filter or strainer i9 disposed in the bottom thereof so as to retain the ground coffee which is placed therein, thus preventing the coffee grounds from entering the depending tube [3. To hold the strainer or filter IS in the position shown there preferably is provided a coiled spring arrangement 19a having one end fastened to the strainer [9 while the other end is hooked around the lower end of the depending tube l3. With this arrangement the filter I9 is readily removable for the purpose of cleaning the upper vessel and washing the same.

To removably relate the unit of assembly 86 to the lower vessel H, the unit of assembly IS includes a cover shaped member 22 which depends from the seat portion ll. This cover shaped portion 22 comprises a depending flange 23 adapted to fit over the upstanding flange i5 of the vessel l l. A suitable resilient gasket 24 is interposed between the flanges l5 and 23 to provide an effective seal therebetween. The resilient gasket 24 preferably includes a lip which extends around the upper surface of the flange [5 to maintain the same in proper position and to protect the upper portion of the lower vessel H. The unit 16 further includes a casing or body portion 28 preferably formed of insulating material and including a downwardly extending portion which defines a depending handle 29. In order to relate the body portion 28, the cover member 22, and the vessel H there is provided a suitable flexible band 25 of metal or the like adapted to be applied to the outside of the flange 23 as is best shown in Figs. 1 and 2 of the drawings. One end 26 of the band 25 is adapted to be suitably fastened within a recess defined in the casing or body portion 28 while the other end is adapted to be tightened by a screw 21 to clamp the flange 23 tightly in position. When this clamping operation is performed the unit of assembly 16 effectively is united to the vessel II and the depending handle 29 serves either to carry the entire coifee maker as assembled in Fig. 1 of the drawings or for carrying only the lower vessel and for pouring coffee from the spout 2| when the upper vessel is removed.

As was mentioned above it is desired to provide an automatic coffee maker having a simplified construction whereby the vessels II and I2 and the unit of assembly 16 substantially comprise the entire coffee maker. With this arrangement the separate stove unit employed heretofore is entireiy dispensed with. In order to heat water which is placed in the lower vessel ii there is provided in accordance with the present invention an immersion type heater 3| which extends downwardly through the mouth M of the lower vessel ll to a level closely adjacent the bottom of the vessel for heating the water as a step in the coffee making operation and also if desired for subsequently maintaining the coffee at a predetermined temperature after it has been returned to the lower vessel H. As illustrated the immersion heater 3! is preferably a sheathed type of heating unit, with the terminals thereof respectively designated at 32 and 35, best shown in Figs. 3 and '7 of the drawings. The heating unit 3| is physically supported from the unit of assembly i6 and the terminals 32 and 35 thereof are disposed within a suitable control mechanism chamber deiined by a recess 30 in the body or casing 28. It will be understood that an automatic control operation necessitates controlling the current supply to the immersion heater 31 from a suitable source of electrical energy which preferably is connected to the pin type contacts 34 and 43 disposed within a recess 33a. defined within the body or casing 28. As illustrated the terminal 32 of the immersion heater 3| is connected by a conductor 33 directly to the pin terminal 34 while the other terminal 35 of the immersion heater 3| is connected by a conductor 36 to the fixed end of a spring strip 31 mounted within the recess 39. The spring strip 3'! has a free end upon which is mounted a contact 38 adapted for engagement with a fixed contact 39 which is supported from a stationary conductor bar ll extending across the recess 30 and fastened to the body 28 by screws 46 at either end thereof. The fixed conductor bar 4| is connected by a conductor 42 with the terminal pin 43. The terminal pins 34 and 43 are male or bayonet type contacts adapted to engage with a suitable socket contact associated with the wellknown power cord extensively used with most types of home appliances. From the above description it will be apparent that the electrical circuit for the heating element 3i best shown in Fig. 7 of the drawings includes a switch having a stationary contact 39 and the movable contact 38. The spring strip 31 is preferably supported from the body 23 at its fixed end by suitable screws 44.

As was mentioned above, it would be desirable to provide in an automatic coffee maker of the type described thus far, suitable control means for actuating the switch comprising the contacts 38 and 39 to the open position at the instant during the coffee making operation when substantially all of the water in the lower water vessel H has moved by pressure created in the lower vessel H to the upper vessel or chamber 12. In

Fi th rw ngs-therevis illustratedacurve diagram showing the pressure-conditions the lower vessel H of. a coffeemalcer during thecoffiee makingpperation, assuming thatithe switch comprising the contacts 38 and .39 is actuated to the. open-position at the-instant. marked iswitch 101T inzFig. -8=of the drawings. ,It should he under-- stoodzthat the curve diagram of ,-Eig..;8-is intended merely for purposes of illustration.since, .,as will become apparent from the followingdcscription, asubstantial variation this curve will occur depending upon certain variable factors .such .as the number of cups of coffee which .8.118 ,being made "as well as the voltage regulation .of the source of .electrical :energy is connect d to the terminals as and .43. Assuming that .the -.sour=".- e of electrical energy-isconnected to ,the pintype terminals :34. and 43 .attheiinstant of time .indicatedgas; zero time in Fig. 8- of the drawings then the pressure in gthe vessel ,H graduallyjncreases. This .pressure is generated in .the vessel as .the result iof the water vapor produced with the increase in temperature and this pressure reaches aimaximumat about the time the WaterJn the lower vessel reaches the lower-end ,of thetube l-3. -It;has beendiscovered thatwhenthis maximum pressure is obtained the pressure dropsquite rapidly andif the switch wereiactuated tothe open position at the point marked "switchoff in Fig.;8-.the pressure would continue to decrease following which a vacuum would vbe produced in thB.1OWel'-VBSS61 as was mentioned above Whereupon the coffee produced in the upper vessel .12 would bereturnedto the lower vessel. It hasbeen discovered that the maxi-mum pressure obtained 1 employed to: operate the swit h- -.co.mp ing as contacts .38 vand .39 in response-tea decrease in Pressure, followi g, the at ainmen f. a maxim m pressure which mi ht vary considerahlw then positive. and satisfactory operation would -be o btained in allcases, sin e. the pres ure dr p the water .maches th lower end. o the. t be l3 isncu t rapid. and the. above-table indicate tthe-pressure existing t asatisiacto wit h pdintis :very similar-regardless of the mimics. cnpsofrcofiee which arezbeing brewe In accordance ewithrthe embodiment of the illvention illustrated Figs. 1 to 7 of.- the drawings: a pressure responsive mechanism .is provided for opening the, switch comprising the contacts is-positioned near-the bottom ofthe recess amidefined.in Lthe-um't l6 and .isarranged so as atorbe subjected on one side to the pressure within :the vessel ll which isv communicated thereto through the passage 49. Preferablyithe.diaphragmjd] is stretched across acup-shaped member-.whichdefinesapressure chamber 48CO11I1B0138dib5 l'2h8 pas-v sageway 38 with the interior of the lower ivese sel H. The other sideof the diaphragm -is sub jected to atmosphericpressure.

-In order that a 1 decrease in pressure following an'increasein pressure to a maximum will-cause the switch comprising contactsi38and39 to open, there is mounted-for engagement with thesu-rface of the diaphragm 4'. :remote from the pressure chamber-"c8 a latching member lfi-havinganotch .Number f Maximum Pressurc- -l\laximumYacuuI of Attained in the fg fi gg g g v Produced inLcwer Cups Lower Vessel 5 pane "Vessel l 2'cups 1:8 of-Mercury 0.3 of Mercury l.6" of Mercury. 4 cups 2.6 of Mcrcury 0.2, of Mereury. -2,5 of Mercury. 6 cups 2.7 QLMercu -y 0.3" of Mercury... 22 of Mercury. -8'cups 3;0-0f- Mercury 0.4 of Mercury 5"of Mercu y- From the above table it is apparent that a pressure :responsive device set to *operate at a predetermined pressure would be'entirelyunsati-sfactory to *controlthe coffee=making operation. For "example "if the pressure responsive device were set to-operate when the'pressure -reached 1.8 of mercury then satisfactory operation would beobtained for making two cups of cofiee but this pressure would be attained, when making more than two cups, long before all of the water the lower vessel had been displaced so i that obviously a; much diluted and unsatisfactory hr-ewwould be obtained. 0n the ot-herhand 'if'thepressure -re- 'spons'ive device were se't'to operate at 3- inches of mercury then satisfactory operation would'be obtained when B cups'of co'iiee were made, but when less than 8 cups of coffee were made this-pressure would never be obtained and theswitch comprising the contacts-38' and 39 would never==open so *thatthe lower coffee vessel "I i: might be destroyed particularly when made of glass. "Because of this non-positive operation pressure-responsive devices prior to the present invention-have loeen iiounri unsatisfactory and have not been employed in commercial coffee makers. I 'ihave discovered however that if-a pressure responsive device-were 62 defined therein ensaseahle wit an extension of the sprin member-31. The notch-.62; preferably has a square shoulder at its up-per end and abeveled face nearits lowerend. .Whenthe diaphragm 4'! i ,inits undistorted condition as shown in Fig. 4. of thedrawings the-notch 162 of the latch member d5 vis out of engagement with the end. of thespring members]. However upon an increase .inpressure the diaphragm-=41 is distorted in themahner shown inF g. 5 f the drawings to cause upward movement of the latch member 35 whereupon the. notch-$2 engages the endofthe spring lever .31, ,If downward move, ment of .the diaphragm it? .causes downward movement of thelatch member 6,5, it will heap.- parent that asubsequent decrease in pressure p rmitting the d a hragm s1 which is inherently biased toits normal position shown in .Figs. A andfi toreturn to such normal position ,-thentfhe spring lever .31 which is in. enga ement ith t e square shoulder of the patch .62 ismoveddownwardly so .astcm ve the co tact 1 out of eneasement with the fixed or stationary contact 39, thereby efiectively interrupting the current flow tothe immersion heaterBlj In order to mount the'latch member 45, so'as to move in both directions withmovement of the drawings.

the contacts 38 and 39.

diaphragm 41 there is provided a bell crank lever pivotally mounted on a rod 52 suitably supported within the recess 30 of the body or casing 28. The bell crank 5| is illustrated as having duplicate arms spaced apart so as to provide means therebetween for pivotally supporting the latch member 35 as indicated by the pivot point 55. The upwardly extending arms of the bell crank 5| are attached to a suitable finger manipulating knob 53 extending through a suitable slot in a cover member 50 for the recess 3|). The arms of the bell crank 5| to which the latch 45 is pivotally mounted comprise an extension or abutment 54 adapted to engage the top of the diaphragm 41. A suitable spring 5| associated with the shaft 52 for supporting the bell crank 5| constantly urges the abutment 54 against the diaphragm 41 thereby insuring movement of the latch .5 with the diaphragm 47. The latch member 45 is provided with a forwardly extending arm 56 and a rearwardly extending arm 58. The forwardly extending arm 55 is adapted to engage a fixed stop 5'! located just above the diaphragm 41 and supported outside the boundaries of the diaphagm 4'! as indicated in Fig. 3 of the The rearwardly extending arm 58 of the latch 45 is connected by a suitable tension spring 59 to a portion of the bell crank 5| so as to constantly urge the latch member in a clockwise direction about its pivot 55 as viewed in Fig. 4 of the drawings. It will be apparent that the spring 5| causes the abutment 54 to remain in contact with the diaphragm 41. The spring 53 furthermore will tend to bia the latch 45 into engagement with the spring arm 37. During the cofiee making operation the diaphragm is distorted to the position shown in Fig. 5 of the drawings so that the notch 62 engages the end of the spring arm 31. Upon the completion of the cofice making operation the parts of the control mechanism are as shown in Fig. 6 of the drawings and the function of the control knob 53 is to cause resetting of the switch comprising the contacts 33 and 33 by moving the notch 52 relative to the end of the spring arm 31. This is accom plished by manipulating the knob 53 to cause slight clockwise rotation of the bell crank 5| as viewed in Fig. 6 of the drawings. This causes downward movement of the pivot point 55 of "the latch 45 and since the forwardly extending portion 56 cannot move downwardly by virtue of the stop 51, the latch 45 is pivoted in a counterclockwise direction about it pivot 55 to release tiation of a subsequent coffee making operation. It is often desirable at the completion of the coffee-making operation to maintain th coffee which is then disposed in the lower vessel at a' suitable temperature of the order of 180 F. or .thereabouts. In order to accomplish this there is provided a thermostatically controlled switch connected in parallel with the switch comprising This control means is illustrated as comprising a bimetallic strip 53 having one end thereof suitably supported within the recess 33 while the other end supports a mov able contact 54 engageabl with a stationary con- .tact '55 supported by the member 4| and electrisally connected with the stationary contact 39. The contact 54 is suitably insulated from the bimetallic strip 53 and is effectively connected by a conductor 65 to the terminal 35 of the heatin lil element 3|. As illustrated the conductor 66 is connected to the screw 44 which in turn is connected by the conductor 36 with the terminal 35. The contacts 64 and thereby provide a switch which parallels the switch defined by the contacts 38 and 39. The bimetallic element 53 is designed to cause opening of the switch comprising the contacts 54 and 35 at temperatures in the neighborhood of 180 F. It will be apparent that during the coffee making operation the switch comprising the contacts 64 and 55 will open when the temperature exceeds 180 a is indicated by Fig. 5 of the drawings and this switch comprising the contacts 64 and 55 remains open until the temperature has been reduced to approximately 180. At the completion of the cofiee making operation when the contacts 38 and 39 are separated as indicated by Fig. 6 of the drawings the bimetallic element 63 will open and close the heating circuit as the temperature of the coffee increases and decreases thereby maintaining the coffee at the desired degree of temperature for serving. It will be apparent that the control provided by the bimetallic element 63 in no Way disturbs the operation of the pressure responsive control means described above.

It will be understood that the recurrent operation of the switch comprising the contacts 64 and 65 will continue so long as the power cord is connected to the pin type contacts 34 and 43 or in other words so long as the coifee maker is plugged into the current supply.

In view of the detailed discussion included above the operation of the coiTee maker of the present invention will be readily understood by those skilled in the art. Briefly however any desired quantity of water commensurate with the amount of coffee to be made is placed in the lower vessel H and coffee grounds also commensurate with the amount of coffee to be made are placed in the upper vessel It. The coffee maker is connected to a suitable electrical outlet when the knob 53 is actuated to rotate the bell crank 5| in clockwise direction as viewed in Fig. 4 with the resultant lowering of the pivot point 55 and swinging of the latch member 35 in a counterclockwise direction to free the notch 52 from the end of the spring strip 31. This action permits the contact 38 to move into engagement with the contact 39 to close the heater circuit. Under these conditions the parts assume the positions indicated in Figs. 4 and 7 of the drawings. It will be apparent that the current flowing through the immersion heater 3! causes the water to be heated with the result that the production of a water vapor pressure within the vessel somewhat in accordance with the curve shown in 8 of the drawings occurs, As the pressure rises the water is forced from the lower vessel through the depending tube l3 into the upper vessel I2 and a maximum pressure is reached at the time the water level in the lower vessel reaches the lower end of the depending tube l3 when a rather rapid decrease in pressure occurs. The diaphragm 4'! responds to this increase in pressure so as to move the bell crank 5| in a counterclcckwise direction and the latch member 45 upwardly so that the notch 62 therein engages the end of the spring strip 31. This position of the mechanism parts is indicated by Fig. 5 of the drawings which also shows that the temperature is sufiiciently high so that the thermostatically controlled switch comprising the contacts 34 and 65 is open. Such increase in pressure to distort the diaphragm 5'! does not disturb the contacts 38 and 39 which remain. closed. The maximum pressure which isattained during the coffee making, operation. may vary widely with the result that: for very high. maximum. pressuresthe latch 45 may move so that the notch 62-. overrides the end of the spring strip. 3:? whose upward? movement: is limited by the contact 39. Immediately following the attainment. of: suchmaximumrpressure point. the water. vapor or steam pressure in the: lower vessel H escapes through: the tube [3 with the resultant sudden pressure. drop in. the lowervessel: l l substantially as indicated-in- Fig. 8 of thedrawings. This sudden drop in pressure causes'the diaphragm M to move to the position shown inzFig; 6- of the drawings. Under the influence of the spring it the latch 45- also moves downwardly and with it moves spring member 37. to open the switch comprising contacts 38' and 39. with: the resultant deenergization of the heater circuit3 l The control structure may bearranged toopenitheheater circuit at any desired-point as an incident to this sudden drop or decrease or pressure within the vessel l I which point is designated; as: the sw-itch-oifpoint' in- Fig. 8 of the drawings. At this step the coffee liquid is brewing in the upper vessel; This brews as the lower vessel cools and as a consequence of the vacuum which forms in the lower vessel the liquid will passthrough the filter ['9' into the lower vessel H as is well known in the coffee-making art. Thiscompl'etes the coffee-making operation and the thermostatic control switch comprising the contacts 64 and 65' will maintain the cofiee in the lower." vessel hot at the desired temperature for serving until the'coffee maker is disconnected from the power sup-ply; With the above described arrangement the switch 01f point occurs at a predetermined pressure under all conditions. Consequently,- it is necessary forsatisiactory operation that the switchoff point occurs at a lower pressure than the lowest maximum pressure likely to occur.

It will be understood that other suitable mechanisms for onerating'the control switch in response to a decrease in pressure following'the attainment of a maximum pressurewill readily suggest themselves to those skilled in the art. For example instead of employing the mechanical latch 45 a permanentmagnet mightbe employed which-moves toward an armature fastened tothe end of the spring arm 31 when the diaphragm is distorted by pressure, so that subsequent'downward movementof the diaphragm t? will move the armature, which is now'within the coercive-range of the magnet, and consequently the spring arm 31.

A preferred embodiment of the present invention is illustrated in Figs. 9 to 12 of the drawings where the corresponding parts thereof are designated by the same reference-"numerais. In this preferred embodiment the switch-ofipoint occurs automatically'in response to a predetermineddecrease in pressure from the maximum pressure attained, and the magnitude of this maximum pressure may have any reasonable value. The switch-off point therefor does not occur at the same predetermined pressure, but rather at the same predetermined decrease from the maximum. The vessels I! and I2 and in fact everything except the unit of assembly which is. designated by the reference numeral H3 in Fig; 9 of the drawings may. be-identical with the ararngernent described heretofore. In this arrangement the unit ofzassembly. H1 includes thebody portion H very similar to the body portion. 28' referredito" above whichterminates ina dependinghandlelt; However the outwardlyextending" sealing: flange I37 and the. cover member 22 of the coffee maker described above are. eliminated and instead-the body portion 11 has integrally formed therewith a suit-.- able molded insulating material, the portion; H of which defines the member for sealing engagee ment with the resilient member l8 as, well as the pouring; spout, and; the portion it which provides the cover member-adapted'to extend. over theelipstanding flange l5 and the resilient-gasket mem: ber 24'. It will be understood that such a cover member is sufficiently resilient to be capable of being slipped over the-upstanding flange t5.. For the: purpose or relating the cover. member [5 which isan integral 'part of the body ll to-t he vessel I I, there is provided a suitable metal band '16; disposed in a recess formed in the dehfindmg flange E5 of the cover member it; This band it is: fastened at one end to the bodymember and at theother end to an over center typemember H so. that manipulation of the: member T1 will tighten orreleasethe band it and conse quently' fasten or remove the unit assembly 1-0 with reference to the container 11-.

As in the construction described abovethe body creasing 7i isv provided with a recess 31') for the control mechanism and a recess 39afor the pin type contacts 34 and 43 respectively;

Disposed near the bottom of the recess'afl; is a pressure responsive device,- in the form; of a diaphragm '68 whose lower surface is directly res-ponsive to the pressure within the vessel H. The upper surface of thev diaphragm i8 is; subjected to atmospheric pressure by virtue of a ventlfl connecting the interior of the recess ttto. atmosphere. This diaphragm 1% has its; periphery sealed'into a circumferential recess defined in-the bodyportion "H whereby the diaphragm T8 is effectively an integral portion. of the body. or casing I I. In order to control the coffee makingoperationthe. switch comprising the contacts 3.8 and 35 is disposed within the recess 30; As. illustrated the contact 38' is supported on a lever 83 pivotallymounted at B! to suitable bifurcated supporting means 82 mounted within the recess 39. The member 89 furthermore'is providedwith a projection 83' which is. in. engagement with the face of the diaphragm T8 remote from'the vessel H. The. lever to is furthermore biased by means of a conducting fiatspring'member tfiyso that the extension 83 is always in engagement withthe diaphragm 78. As is best shown .inFigs. 1.1 and 12, of'the drawings the contacttt is connected to the pin type terminal 3 i through a suitable conductor 65, and the springsfi which is connected to the lever 89, which lever ispreferably formed of conducting material. The projection 83 from, the lever 89- is preferably; formed of an insulatin material.

The contact 39 is supported on a lever 81' also 'pivotally mounted as indicated at BBrbetWeen-the two portions of the bifurcated support 82. A pair of friction'washers. 8,9 areydisposed between thebifurcated portions 82 and thelever 81, which levert'! ispreferably formed of insulating material. As illustrated the lever 81 has an extension to the oppositeside of the pivot 88 from the contact 39 which supports an upwardlyextending member. 9|. The portion of the'l'ever 81 to the right of the-pivot 88 as viewed in Fig. 11 also has an upwardly extending member 9-2. The purpose of the members 9| and 92 will become apparent as the. following descriptionproceed's. To complete the electrical-circuit. through the switch comprising the contacts 38 and 39 the contact 39 is connected by means of a conductor 93 with the terminal 32 of the heating element 31.

The terminal 35 on the other hand of the heating element 3! is connected directly by the conductor 94 with the pin type contact 43.

With the arrangement described and the contacts 38 and 39 in the closed position shown in Fig. 11 of the drawings the coffee making operation will proceed in the same manner as was de- I scribed in connection with the arrangement shown in Figs. 1 to 7 of the drawings. As the pressure in the lower vessel I I increases the diaphragm I8 is bowed upwardly with the result that the contact 33 is moved upwardly through pivotal movement of the lever 80- Since the contact 39 is mounted on a. pivoted arm 8'! it also moves upwardly but remains in conducting relationship with the contact 38. When the maximum pressure has been obtained resulting in the maximum upward movement of the contact 38 there follows the subsequent decrease in pressure discussed above so that diaphragm !8 returns to the position shown in Fig. 11 of the drawings and spring 88 causes contact 38 to move to its lowermost position. However the friction washers 89 described above hold the lever 81 in the uppermost position attained thereby so that contact 38 moves away from contact 39 to open the circuit in the same manner as was accomplished in the previously described embodiment, except that the circuit is open following a predetermined decrease from the maximum rather than a decrease to a predetermined pressure.

The projection 92 is effectively a reset but- I completely enclosed by a cover member 95 which may even be integral with the body or casin II if desired. This cover member 95- is provided with a pair of openings for the projections 9| and 92 which are preferably closed by suitable resilient plugs or sealing gaskets 91 and 98 respectively, best shown in Fig. 11 of the drawings. These plugs may be distorted to actuate the buttons 9| and 02 without displacing them from their position closing the openings in the cover member 95. Preferably the sealing members 91 and 98 are provided with suitable indicia such as" Off and On respectively to indicate the function of the particular control button which is actuated by pressing on the resilient sealing members 97 and. 99.

' It will be apparent that a very simple control device is provided in the embodiment shown in Figs. 9 to 12 inclusive which employs a pressure responsive device responsive to a predetermined decrease in pressure from the maximum following the attainment of a maximum pressure. It should be understood that if desired a suitable control means for maintaining hot the coffee in the lower vessel following the completion of the coffee making operation may be incorporated which may take the form shown in connection with the first described embodiment ofthe present invention.

In view of the detailed description included above the operation of the coffee maker of the preferred embodiment of the present invention will be apparent and no further discussion thereof is included herewith. It will furthermore be understood that there has been provided a simple type of coffee maker employing a pressure responsive device which is fool proof in operation and unlike the prior art pressure responsive devices employed in coffee makers insures proper control of the coffee making operation regardless of the variables involved.

There are some people who feel that coffee should only be made in a glass vessel to insure the best possible taste. However, it is obvious that any frangible vessel such as a glass vessel is subject to breakage unless handled with great care at all times. This has been a decided deterrent to the use of glass vessels for coffee makers.

In Fig. 13 of the drawings there is illustrated a modification of Fig. 9 in which the advantages of a frangible coffee making vessel are retained without the disadvantages with respect to the fragility. As illustrated the corresponding parts of Fig. 13 are designated by the same reference numerals as in Fig. 9. The same lower vessel I I, preferably formed of glass which is a frangible material, is illustrated. However, the unit of assembly generally designated at 10' is slightly different from the unit of assembly I0 of Fig. 9 in that the body portion II thereof includes a cover portion I00, which is effectively a portion of a protective shell for enclosing the frangible vessel II, and encloses a much greater portion of the glass vessel I I than the portion I5 of Fig. 9. The cover portion I00 includes a shoulder portion I00a for conforming with the peripheral flange I5 and the rubber gasket 24 as is clearly shown in Fig. 13 of the drawings. The cover portion I00 further includes a flanged portion I OOb which is threaded to receive a cooperating cup shaped shell portion IOI, having a threaded portion IOIa so as to engage the threaded portion of the cover I00 to define a shell for completely enclosing the exterior of the vessel I I.

Preferably the bottom of the member or shell portion MI is provided with suitable leg portions I02 which might comprise an annular protrusion or a lurality of individual protrusions. A suitable resilient cushioning means I03 which might comprise a rubber pad or a coiled spring, as shown, cushions the base of the glass vessel II and also maintains the peripheral flange I5 in sealing engagement with the gasket 24, and the gasket 24 in turn against the shoulder I00a of the cover member I00. The resilient cushioning means I03 effectively shock proofs the tangible vessel II which furthermore might be termed an inner liner for the protective shell comprising the portions I00 and IIII. The glass Vessel II can readily be inserted into the bottom of the cover member I30 whereupon the cushioning means I03 and the member IOI are assembled in the manner shown. A predetermined space is maintained between the outer protective shell, comprising the members I00 and IOI, and the vessel I I.

The cover member it!!! may be formed of molded insulating material integral with the body portion H as may also the member I CI. It should be understood, however, that th protective shell for the vessel Ii might also be formed of any suitable metal or other material. In this way the coffee maker effectively com prises a glass vessel II for containing the coffee whereb the waterinav "be h a ed a glass vesso! and t e same-time a sretective shellis pro ioled herefor n a simpleanner hiCh'P 9- teetiv shell b d signed o have y p asineappe ane addit on to performin its function i mplete y protectinethe gl s v el H- with t s ons u o the c ee maker may beihandled a r he 'o reless man er Withou dama inghe lass vesseland s aresul he in herent dis d nta e of the ass oifee maker is completely overcome'while still retaining the desirable features thereof. The frangible vessel H which effectively; isa-glass liner canreadily be renlao dif or-some u f es en reason itis dama ed, Furthermor the-unit of a em ly cluding the immersion heater 3L and control means associated therewith is admirably suited tobe combined with the shock: proofshell or.- raneeme tdis ed in 7.

While there have been illustrated and described or ainparticular em odimen s of he pres nt invention- .it' will be unde s ood that vari us changes and modifications of theinventio will occureto those skilledinthe; art. It is aimed in the'appended-clai-ms tocover all such ch n and mod fications as fall Within the truespirit and scope of, the present invention.

What is desired to be secured by Letters Patent of the United States 11 A coffee maker having, in combination, a coffee infusion vessel having a depending, tube, an openstop vessel: adapted for containing water to, be heated, a unit of assembly detachably mountedonthe water v ssel, saidunit providin a cover enclosing-the-opentop of the'water vessel and providing an opening forspassage of said tube into the water vessel, Said unit serving to sealthe ton of the water: vessel so that watermay be displaced'fromisaid Water vessel to" the infusion vessel through said tube: in response to pressure generated'withinthe water vessel, said unit equipped with an immersion heating element depending into the Water vessel, a diaphra m Within said unit responsive to I pressure in the water vessel, aneleotric circuit for the heating element including a switch device within the' unit coacting with said diaphragm, said heater circuit being closed for starting the coffee mak ng o era ion s t thaa ed W t r will e i p aoedto heinius on ve s l in re p nse t Pr ssu e W h n e Wa er v seli s idi phra m being, responsive: to said pressure in the water vessel andcoactingvvithsaid switch toiopen' the heating circuit after amaxiznum pressure has been reached inthe water vessel incident to dis- Dlaoement of water therefrom in th cofiee male- .ingoperation andafter the pressure has dropped placemen Av coffee. maker having, in combination, a cofiee infusion vessel having adependingv tube, an, Open-top vessel adapted for containing water to be. heated, a unit of assembly detachably mounted Onthe water vessel, said unit of assembly providingacoverv for. the opentop of said water vessel andeproviding an opening for. insertion of said infusion vessel tube into the water vessel, an electric immersion heating element mounted on said unit and depending into the water. vessel, control mechanism for said heatingelement carried by said unit including a switch, for the heatingelement, a pressure responsive diaphragm, means providing communication betweenisaid diaphragm and the interior (ii-the watervessel, andemeans coacting between the diaphragm and the switohto open the-heatingcircuit after a maximumrpressure has been reached'in the Water. vessel incident to displacement of; Water therefrom in the cofiee makin operation and. afte1-- thev pressure has dropped below said maximum following said water displacement.

3. A-coiiee maker having, in combinatioma cofiee infusionvessel having a depending tube, an open-top vesseladapted for containing water to be heated, a unit of' assembly detachably mounted on the water vessel, said unit of as sembly comprising a coverpartishaped to detachably fitrthe top portion of the water vessel to providea cover for the open topthereof and topmvide forinsertion of said infusion vessel tube into the water vessel, aseal-between said unit and the watervessel, and asecond sealbetween the unit cover and the tubular portion of the infusion vessel, said unit includinga casing of insulation material-provided at one endiwith a handle and at its opposite end shaped for attachment to said cover portion and fixedlyattached thereto, an electric immersion heating element. mounted on said unit and depending into the Water vessel, and control mechanism for said heating element carried by saidiunitincluding a pressure responsive diaphragm mounted within said casing, said unit having means providing communication between saiddiaphragm-andithe interior of the Water vessel whereby the control for saidheating element is actuatedby said diaphragm in re;- spouse-to change inpressure withinthe water vessel.

4. A vacuum type coffee maker having, in combination, an opentop lower. vessel, anu ppen V55;- sel havingv a tube adapted to depend into'the lower vessel, means for relating saidupper and lowerv vessels so that-water'heatedin-the lower vesselis displacedby pressure therein and forced through said tube to said upper vesseLthe water vapor pressure in said-lowers vessel beingsharply decreased upon the displacement of suflicient Water from saidilower vesselbelow thetube depending into the lower vessel an immersion heater for heating water in the lower vessel, a unit of assembly applied to thelower vesselfor supporting the heater through v the open. top of the lower vessel, a switch supported by'saidiasem ly for c ntrollin the energize-tion of said heater, a mechanismisupportedtby saidassembly comprising an operating member, movablefrom a first to a secondposition; pressure reversaliresponsive means responsive to a predetermined decrease in pressure in saidlower vessel follow,- ing the attainment of a predetermined maximum pressure therein for moving said operatingmethber from said first tosaid secondv position, said last mentioned means oomprisingan element actuated. directly in response to pressure yin said vessel, and means relating, said operating: memher and said switch so that said switch is Opened in response to said predetermined decrease of pressure.

5. In a coffee making device,xa pressurevessel, means to supply heat to said vessel, an electric circuit for energizing saidameans. to supply heat to said vessel; a switch in saidcircuit comprising a pair of relatively: moveablecontacts, pressure reversal responsive means forw'moving both of said contacts as a unit While in: contacting engagement responseto an increase inpressure" in said pressure vessel, means:- for biasing oneof said contacts in a direction to-follow the movement of said pressure responsive means; and

17 means for holding the other of said contacts in any position to which it is moved, whereby upon a decrease in pressure said one of said contacts moves away from the other of said contacts effectively to open said switch in response to a decrease of pressure in said vessel.

6. In a coffee making device, a pressure vessel, means to supply heat to said vessel, an electric circuit for energizing said means to supply heat to said vessel, a switch in said circuit comprising a pair of relatively moveable contacts each mounted upon a pivoted contact arm, pressure responsive means for moving both of said contact arms while said contacts are in contacting engagement in response to an increase in pressure in said pressure vessel, means for biasing one of said contact arms in a direction to follow the movement of said pressure responsive means, and friction means for holding the other of said contact arms in any position to which it is moved, whereby upon a decrease in pressure said one of said contacts moves away from the other of said contacts effectively to open said switch in response to a decrease of pressure in said vessel.

'7. In a coffee makin device, a pressure vessel, means to supply heat to said vessel, an electric circuit for energizing said means to supply heat to said vessel, a switch in said cir uit comprising a pair of relatively moveable contacts each mounted upon a pivoted contact arm, pressure responsive means for moving both of said contact arms while said contacts are in contacting engagement in response to an increase in pressure in said pressure vessel, means for biasing one of said contact arms in a direction to follow the movement of said pressure responsive means, friction means for holding the other of said contact arms in any position to which it is moved, whereby upon a decrease in pressure said one or" said contacts moves away from the other of said contacts efiectively to open said switch in response to a decrease of pressure in said vessel, and manual means for moving said other of said contacts against the action of said friction means.

3. In a coffee making device, a pressure vessel, means to supply heat to said vessel, an electric circuit for energizing said means to supply heat to said vessel, a switch in said oir I it comprising a pair of relatively moveable contacts, pressure responsive means for moving both of said contacts as a unit while in contacting engagement in response to an increase in pressure in said pressure vessel, means for biasing one of said contacts in a direction to follow the movement of said pressure responsive means, and friction means for holding the other of said contacts in any position to which it is moved, whereby upon a decrease in pressure said one of said contacts moves away from the other of said contacts effectively to open said switch in response to a decrease of pressure in said vessel.

9. In an automatic cofiee maker of the type in which water vapor pressure generated by heatin water in one chamber is used to expel the water through a tube into a coiiee infusion chamber and the heating is then terminated to permit the water vapor to cool and condense and thus cause the coffee liquor to return to said one chamber, and in which the water vapor pressure is appreciably decreased in response to lowering of the water level in said one chamber to uncover the end of said tube disposed in said one chamber; the means for heating the water in said one chamber comprising a heating element, a circuit for energizing said heating element including switch means, a mechanism associated with said one chamber comprising an operating member movable from a first position to a second. position, water vapor pressure reversal responsive means responsive to a predetermined decrease in pressure in said one chamber following the attainment of a maximum pressure for moving said operating member from said first position to said second position, said last mentioned means comprising an element actuated directly in response to pressure in said one chamber, and means relating said operating member and said switch means so'that said switch means is operated to interrupt said energizing circuit in response to said predetermined'decrease in pressure in said one chamber.

10. In an automatic coffee maker of the type in which water vapor pressure generated by heating water in one chamber is used to expel the water through a tube into a coffee infusion chamber and the heating is then terminated to permit the water vapor to cool and condense and thus cause the cofiee liquor to return to said one chamber, and in which the water Vapor pressure is appreciably decreased in response to lowering of the water level in said one chamber to uncover the end of said tube disposed in said one chamber; means for heating the water in said one chamber which comprises a heating element, a circuit for energizing said heating element, a switch means in said energizing circuit, a water vapor pressure reversal responsive device responsive to a predetermined decrease in pressure in said one chamber following the attainment of a predetermined maximum pressure, said device being actuated directly by variations in the water vapor pressure in said chamber and including a control element operative in a predetermined direction in direct response to said decrease in water vapor pressure in said one chamber, and means relating said switch means and control element to open said switch means in response to movement of said control element in said predetermined direction.

11. A coffee maker having, in combination, a coffee infusing vessel, a pressure vessel in which water is heated and from which it is displaced by pressure therein and passed to said coffee infusing vessel, and in which the water vapor pressuris sharply decreased in response to displacement of the water into said coiIee infusing vessel, an electric heater for heating the water in the pressure vessel, a circuit for energizing said electric heater, a switch for controlling said circuit, a water vapor pressure reversal responsive device directly responsive to the water vapor pressure in said pressure vessel and including an element conditioned for operation from a first setting to a second setting in response to the water vapor pressure in said pressure vessel rising to a maximum, and operative from said first setting to said second setting in direct response to said decrease in water vapor pressure in said vessel after said maximum pressure is attain d, and means relating said device and said switch to interrupt said circuit in response to movement of said mechanism from said first setting to said second setting.

12. In a cofiee making device, a pressure vessel, means to supply heat to said vessel, an electric circuit for energizing said heat supplying means, a switch in said circuit, a pressure reversal responsive mechanism operative from a first setting to a second setting in response to a predetermined decrease of pressure in said vessel following the attainment of maximum pressure therein, said mechanism comprising an element actuated directly in response to the pressure in said vessel, and means operatively relating said switch and said mechanism to open said switch in response to operation of said mechanism from said first setting to said second setting.

13. A coffee maker having, in combination, a cofiee pressure vessel in which Water is heated and from which it is displaced by pressure therein and passed to a coffee infusing vessel, an electric heater for heating the water in said pressure vessel, control means for controlling said electric heater, a pressure reversal responsive mechanism directly responsive to the pressure in said pressure vessel conditioned for operation from a first setting to a second setting in response to the pressure in said pressure vessel rising to a maximum, and operative from said first setting to said second setting in response to the pressure in said pressure Vessel decreasing a predetermined amount after said maximum pressure is attained, and means for controlling said control means in response to movement of said mechanism from said first setting to said second setting.

IVAR JEPSON.

References Cited in the file of this patent Number Number UNITED STATES PATENTS Name Date Heideman Mar. 5, 1929 Fonseca Mar. 18, 1930 Smith Feb. 13, 1934 Browning Feb. 9, 1937 Keaton Mar. 14, 1939 Masin June 27, 1939 Pagliuco Feb. 13, 1940 Ireland Apr. 9, 1940 Watson June 10, 1941 Jepson et a1 Jan. 6, 1942 Wagner June 23, 1942 Weeks Jan, 23, 1942 Wilcox Aug. 11, 1942 Allen Feb, 20, 1945 FOREIGN PATENTS Country Date Switzerland Sept. 16, 1933 Germany Nov. 30, 1937 

